Manchester Unity building warns of Metro Tunnel damage

Melbourne gothic landmark the Manchester Unity Building is at risk of cracking from tunnelling for the Metro Tunnel, its owners fear.

The fragile facade of the tower is at risk of cracking from the tunnelling, but the danger is being overlooked, says Kia Pajouhesh, chairman of the Manchester's owners corporation.

The soaring Art Deco building on the corner of Swanston and Collins streets, built in 1932, is renowned for its narrow columns, glass walls and terracotta tiles.

The Manchester Unity Building on Swanston StreetCredit:Eddie Jim

Dr Pajouhesh has accused the authority and the consortium overseeing the project, the Cross Yarra Partnership, of failing to properly assess the building's capacity to cope with vibrations caused by tunnelling under Swanston Street.

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A one-hour property inspection was done on the building in February last year, but the assessment was "substantially deficient", Dr Pajouhesh claims in a scathing eight-page letter sent to the authority.

"We are at a loss to understand the basis behind the decision to use land under the [Manchester] without this critical information," he wrote.

Dr Pajouhesh is the owner of Smile Solutions, which occupies six levels of the building.

"This conduct leaves us with no confidence that the consortium has at heart the interests of the custodians of one of Melbourne's most prized heritage assets."

The 1932 building is one of Melbourne's most beloved.Credit:Paul Rovere

It comes amid revelations that five hairline cracks have emerged on the Westin building as a result of the early works at the City Square construction site.

A spokesman for the authority said the cracks in the building's plasterboard were superficial, would not pose any structural risk, and would be rectified.

The Metro Tunnel project will provide much-needed extra capacity on the city's rail network by allowing more trains to run through the city, outside of the City Loop. Once complete, the project will include five new stations and a nine-kilometre tunnel connecting the Cranbourne-Pakenham and Sunbury lines.

Work is already under way to build the underground Town Hall station at City Square, but tunnelling under Swanston Street will not begin until next year.

The Town Hall station has recently been re-designed to make it larger and more spacious, and that will require more land.

The new designs indicate that tunnelling will occur closer to the Manchester building.

The consortium has already warned that St Paul's Cathedral and Town Hall may have some superficial cracking, but their risk assessment did not include the Manchester building.

"[The Manchester] is much closer to the project's CBD south station site than both St Paul's cathedral and the Melbourne Town Hall," Dr Pajouhesh says.

He also warns that "the grout between the tiles, which contains asbestos, is prone to failure."

Dr Pajouhesh's letter was sent on Tuesday this week, just as Melbourne University warned that the $11 billion underground rail project could damage equipment and facilities in the Parkville Biomedical Precinct.

The university's chief financial officer Allan Tait said he was concerned that vibrations from tunnelling, and electromagnetic interference caused by trains runing through the underground station, would "render critical research equipment inoperable".

Peter MacCallum Cancer Centre has also warned that radiotherapy treatment machines may be affected by vibrations.

The Metro Tunnel spokesman said the authority had been engaging with the owners of the Manchester building since 2015.

He said two property condition surveys were carried out for the building in February this year and a comprehensive condition survey would be done before tunnelling began.

“The project has some of the world's best engineers and tunnelling experts working through these challenges," he said.

A government spokesperson said the building owners' concerns were "the types of issues that are routinely managed on similar tunnel projects in busy cities around the world".